We demonstrated the multilayer nature of the perineurium and the role of intercellular tight junctions in maintaining structural and functional integrity. Passing AC current across the perineurium demonstrated that its electrical properties could be represented by two resistances and two capacitances. A high capacitance, which could be ascribed to polarization of charge, probably represents the properties of the intercellular tight junctions. This project has been temporarily discontinued, pending the expected return during Fiscal Year 1983 of Dr. Ananda Weerasuriya.